Region-Specific Memory Access Scheduling for Stacked-Die Arrays

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Solution Overview

Problem

Conventional memory systems manage performance variations by using conservative timing parameters based on worst-case scenarios, leading to inefficiencies in memory access scheduling due to region-to-region variations in memory cell access times and signal propagation delays, particularly in stacked-die memory architectures.

Innovation Solution

Implementing a memory controller that profiles and stores region-specific memory timing parameters for each region of the memory array, allowing for optimized scheduling of memory accesses based on these variations, thereby reducing latency and improving bandwidth and power efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conservative worst-case timing parameters are used for memory access scheduling, then reliability is improved, but productivity deteriorates

Engineering Contradiction:
Improvememory access reliabilityVSAvoidmemory access efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The memory array is divided into multiple regions, and timing parameters are profiled and stored separately for each region. The memory controller schedules accesses to different regions using region-specific timing parameters rather than a single worst-case parameter set, enabling optimized memory access scheduling that improves productivity while maintaining reliability through region-appropriate timing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different timing parameters are applied to different memory regions based on their specific performance characteristics. The system profiles timing parameters for each region and uses the appropriate regional parameters for scheduling, rather than applying a uniform worst-case parameter set across the entire memory array, thus improving overall memory access efficiency.

Inventive Principle:
Principle #3Local quality

2Productivity

If region-specific timing parameters are profiled and stored, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improvememory access efficiencyVSAvoidmemory controller complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system performs preliminary profiling of timing parameters for each memory region during manufacturing or initialization, and stores these parameters in advance. This preliminary action eliminates the need for complex real-time analysis during operation, as the memory controller can directly use the pre-profiled regional parameters for scheduling decisions, thereby improving productivity without excessive operational complexity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4462270B1Memory system with region-specific memory access scheduling
Publication Date: 2025.12.03 ADVANCED MICRO DEVICES INC
  • EP4462270B1 patent drawingFigure 1
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  • EP4462270B1 patent drawingFigure 3

AI summary

An integrated circuit device includes a memory controller coupleable to a memory. The memory controller to schedule memory accesses to regions of the memory based on memory timing parameters specific to the regions. A method includes receiving a memory access request at a memory device. The method further includes accessing, from a timing data store of the memory device, data representing a memory timing parameter specific to a region of the memory cell circuitry targeted by the memory access request. The method also includes scheduling, at the memory controller, the memory access request based on the data.